Multi-color lamp



W. C. DAUSER MUL'II-COLOR LAMP Oct. 3, 1967 2 Sheets-$heet 1 Filed Nov.23, 1964 INVENTOR. MMAW '6. 04.416?

ATTORNEYS 0st. 3, 1967 w. c. DAUSER 3,345,509

MULTI-COLOR LAMP Filed Nov. 23, 1964 2 Sheets-Sheet 2 INVENTOR. Mal/4A7a! 44MB? Big; ZZ

ATTORNEYS United States Patent 3,345,509 MULTI-COLOR LAMP William C.Bauser, 458 Melody Lane, Muskegon, Mich. 49445 Filed Nov. 23, 1964, Ser.No. 413,231 Claims. (Cl. 24020) This invention relates to colorphotography and photographic printing, and related fields, and moreparticularly to a lamphouse for photographic printing and enlarging.

This is a continuation in part of my co-pending applications entitled,Color Head, filed May 17, 1962, Ser. No. 195,476 and entitled, ColorControl Method and Apparatus, filed May 17, 1962, Ser. No. 195,501.

The novel lamphouse is useful for many fields of endeavor involving theproduction of controlled colored illumination. Since however, the devicewas developed for and is uniquely suited for color photography,including color analyzing, printing, enlarging, and standardizing, itwill be described and explained with respect thereto. The invention hasparticular adaptability to subtractive multi-layer dye coupling typeprinting paper, such as the three-layer type sheet paper currentlyavailable.

The lamphouse enclosed and claimed in the above identified applicationSer. No. 195,476 was designed to simultaneously activate all threelayers of such paper, in an accurately controlled manner by employingthree different independent light sources of primary colors to form thewhite or off-white exposure light. This is combined with a specialsystem to direct the light along a central axis.

This prior system works well for equipment such as that taught in theapplication, but, when used in combination with less sensitive exposurecontrol equipment, sometimes results in color unbalance and unevenillumination, coupled with insuflicient illumination over some portionsof the print and easel. These characteristics combine to prevent topquality printing.

It is therefore an object of this invention to provide a novel lamphousethat enables top quality printing, enlarging, tionwith low sensitivityexposure control equipment.

It is another object of this invention to provide a color head of highquality, controlled light output of desired characteristics, forsimultaneous exposure of all three layers of three-layer type sheetpaper, while aflording completely adequate and uniform illumination foruse with even low sensitivity control equipment. Excellent printing canbe achieved even with inexpensive paper, A negative can be controllablyimproved to a. better quality.

print.

Another object of this invention is to provide a light head ofsimplified construction while affording. excellent uniformity ofillumination of the controlled color light. This is achieved uniquely byoptically converting the separate light sources arranged in a threedimensional pattern, into a two dimensional or planar, combined lightsource of even illumination characteristics.

Still another object of this invention is to provide a light head ofthree dimensionally arranged primary color sources which optically forma secondary planar source while achieving the convenience and localcontrol of conventional single exposure equipment, but the purity ofsaturation of conventional multiple exposure equipment, image definitionsuperior to both, and balanced illumination with intensity sufficientfor accurate intensity-control of each primary color source.

These and sever-a1 other objects of this invention will become apparentupon studying the following specification in conjunction with drawingsin which:

FIG. 1 is a perspective view of the novel color head;

and color analysis even when used in combina-= may, for example, be ofthe type marketed by Bausch &

' upon which is coated -metals. The total thickness is normally nogreater than 60904-54 0. In each case the first -whether the selector isa 'mitter. The third defines number is the wave ice FIG. 2 is aperspective view of the color head with the housing cover removed;

FIG. 3 is a plan view of the uncovered head in FIG. 2;

FIG. 4 is a schematic ray diagram of two of the light source componentsand the two related diifuser elements essential to this novel colorhead;

FIG. 5 is a schematic, plan, ray diagram of the structure in FIG. 4; and

FIG. 6 is a schematic circuit diagram for the color head.

Referring now specifically to the drawings, the complete head 10includes a mounting base 12 to which a cover 14 is attached by asuitable means such as the threaded fasteners 16. The top of the housingis open at 18 for attachment of a cooling blower (not shown), Electricalinput to the housing is made through cord 20.

Housing shell 14 can be removed from base 12 as shown in FIGURE 2, byremoval of screws 16. This exposes the interior of the housing, and morespecifically, the light source components with their correspondingselective filters.

- These light sources G1, G2, B1, B2, and R1 and R2 are arranged in aparticular geometrical cluster. More specifically, the two lights G1 andG2 to supply the green red light. Each of these lights is basically awhite light source, composed of all of the spectral components. Eachlight includes a globe 22 enclosing a filament 24 which .is electricallyconnected through the slide connector block 26 to power supply means inthe electrical connector socket 28 of generally rectangularconfiguration. A reflector 30 may be either external, or coated on theglobe, -or internal of the globe, to orient the light toward the centerof the structure, and dichroic filters provided.

The dichroic filters are each mounted in the upright extension 40 ofbase 12 as shown by filter 42 for light G2, which is shown in FIG. 2removed from its slide socket 28. The lights and dichroic filters areseparated by batfies 44. These dichroic filters are preferably the typeknown as spectral selectors. Each is constructed to pass only oneparticular wave length range of light while reflecting the remainingwave lengths. More specifically, the spectral selectors forbulbs R1 andR2 to allow red light to pass is composed of a transparent base such asquartz or glass a multiple of coatings of rare earth more specificallythrough the about 40 microinches. These multiple coatings are placeddirectlyone upon another, without any intermediate material being placedtherebetween. The selectors are placed perpendicular to the central axisof the light beams. They Lomb and identified as Red Selector -2-600 ascoupled with 90 2-540, Green Selector 90-4-540 as coupled with 90.2480,and Blue Selector 901480 as coupled with number identifies the angle ofincidence of the light, i.e., the 90-degree angle as illustrated in thedrawings. The second number is a Bausch & Lomb design designation whichindicates short, long, or band wave transa functional wave length. Ifthe filter has a single cut-01f which must be defined, this third lengthin millimicrons at the 50% transmittance point on this cut-off. This,for example, is true for. the blue multifilm selector which passes wavelengths below the visible range of about 400 millimicrons (ultra-violet)as well as blue. This also is true for the red selector which passeswave lengths above the visible range of about 700 millimicrons(infrared) as well as red. The

hemisphere 60 acting as a light globe. However,

3 green filter, on the other hand, falls in the middle of the visiblerange from 400-700 millimicrons wave length and possesses two cut-offs.Its third number, therefore, refers to the wave length at the center ofthe band transmitted.

subtractive filters and achieve controlled wave length transmission ofselected colors.

The three primary colors red, green and blue, when in equal proportions,constitute means for forming white light of pure characteristics. Uniqueto this disclosed structure is the placement of the green, red and bluerespective pairs of lights opposite each other, i.e., in a pattern formof equal spacing around the periphery of the structure, and equallyspaced from the center line 50 (FIG. 4).

As a consequence, using the red lights R1 and R2 as examples, thesetransmit light from their respective filaments through their spectralselectors and oriented toward a planar opal diffuser or frosted glassplate 54. Referring to bulb R2, the light transmitted from its filamentstrikes the opal diffuser 54 across its center line in a pattern area sothat the shorter rays are of length A and the longer rays are of lengthB as shown. However,'the illumination in the area is equal and balanced,since the oppositely positioned bulb hasjust the opposite effect, sothat the cumulative light achieves uniform illumination. Actually, ithas been determined by experimentation that the planar opal diffuser 54serves as a screen for the formation of an image I of the filament F ina generally ovular area like that illustrated in FIG. in two dimensions.This area is evenly illuminated over its extent. The filament image istherefore planar, and is on the axis or center line 50. With all sixbulbs, or even more in equal numbers, the three ovular areas, of whichtwo are shown in phantom in FIG. 5, together effect a simulated lightsource of planar or two dimensional characteristics on the center lineof the system. In order to be useful, the planar diffuser, acting as ascreen, must be combined with an underlying hemispherical diffuser 60adjacent thereto, to diffuse the light from the simulated filamentsources on diffuser 54. It will be realized that this combination actsin effect like an actual light with a filament image on diffuser 54, andwith opal the fila ment image is planar and superior to a threedimensional filament for photographic purposes. Hence, the result issuperior lighting with balanced illumination, increased in tensity ofillumination, and uniformity of diffusion over the area beneath the opalhemisphere where the easel would be mounted when the head is used forphotographic purposes.

To achieve equal illumination of each pair of lights, a circuit asillustrated in FIG. 6 is employed. This includes a suitable electricalconnector 70 preferably in a form of an electrical timer when thestructure is used for photographic purposes, a selector switch 72,transformer means 74, and the plurality of independent circuits for red,green and blue light. More specifically, the multiple throw switch 72includes three selectors operated in gang fashion, with seven selectedterminals for each of the three selectors, to enable different colors tobe formed by varying the red, green, and blue primary input intensities.Thus,with the switch in position 1, for example, contact is made solelywith the circuit through transformer coils 76 for the red bulbs R1 andR2. Contact 2 causes connection only through coils 78 for green bulbs G1and G2. Likewise, contact 3 causes only blue light through transformercoils 80 and blue lights B1 and B2. Contact 4 combines red and green andblue, No. 5 combines blue and green, No. 6 combines blue and red, andNo. 7 comspherical opal diffuser.

Conceivably certain additional advantages of this novel structure willoccur to those in the art upon studying the foregoing specifications anddrawings. Also, since changes in detail could conceivably be madewithout departing from the concept presented, the invention is to belimited only to the scope of the appended claims and the reasonablyequivalent structures to those defined therein.

' I claim:

1. A lamphouse with controlled, balanced, even illu- .mi nationcomprising: a plurality of variable intensity, .prlmary color, lightsources for three primary colors,

arranged radially around a central axis, and positioned to focus at aposition located on said axis; at least two sources for each primarylight arranged at equal intervals around said axis, opposite each other;a planar diffuser element positioned on said axis at said position toreceive the focused primary color light components and combine them intoa secondary light source, and to diffuse the combined light whiletransmitting it; and a hemispherical diffusor on said axis spaced fromsaid diffusor element to receive light from said element and transmit itevenly to an area to be illuminated.

2. A lamphouse with controlled, balanced, even illumination comprising:a plurality of variable intensity,

primary color, light sources for three primary colors, arranged radiallyaround a central axis at equal spacings therefrom, and positioned tofocus at a position located on said axis; configurated reflector meansbehind each of said sources causing stray light therefrom to be focusedat said position on said axis, at least two sources for each primarylight, arranged at equal intervals around said axis, opposite eachother; a planar, opal diffusor element positioned on said axis at saidposition to receive the focused primary color light components andcombine them into a planar secondary light source; and a hemisphericaldiffusor on said axis adjacent said diffusor element opposite said lightsources, to receive light from said element and transmit it evenly to anarea to be illuminated.

3. A lamphouse with controlled, balanced, even illumination comprising:a plurality of variable intensity, primary color, light sources forthree primary colors, arranged radially around a central axis, andpositioned to focus at a position located on said axis; at least twosources for each primary light, arranged opposite each other, and commonvariable power supply means to both of said two sources for each color,for completely balarranged radially around a central axis, andpositioned to illuminate an area located on said axis; spectral selectormeans for three primary colors between respective sources and said area;each of said primary colors formed from at least two sources, thesources of each of a given primary color being spaced at equal intervalsaround said axis; the number of sources of each of said primary colorsbeing the same; a dififusor element located on said axis at said area toreceive and combine the primary light illumination into a planarsecondary source; and a hemispherical opal diffusor on said axis beneathsaid dilfusor element, receiving the combined light therefrom andtransmitting it evenly to an area to be illuminated.

5. A photographic printing lamphouse comprising: a plurality of an evennumber of light sources arranged radially around a central axis, in aplane; said sources including configurated reflector means focusing thelight to a common position along said axis displaced from said plane;the beams of said sources all converging from said sources to saidposition; a planar opal difiusor plate located on and normal to saidaxis at said position; said light beams each being focused on said platein the shape of an oval; spectral selector means between each of saidsources for three primary colors to produce an even number of sources ofeach primary color; said sources for each primary color being positionedoppositely across said axis to balance the illumination of the ovalpattern for that color; the combined ovals forming a controlled planar,white light source on said axis; and a hemispherical opal difrusor onsaid axis, spaced from said plate, receiving the combined light anduniformly illuminating an area beyond it.

References Cited UNITED STATES PATENTS NORTON ANSHER, Primary Examiner.F. L. BRAUN, Assistant Examiner.

